Multiple groove expanding pulley



Feb. 25, 1936. v JANNIN I 2,031,712

MULTIPLE GROOVE EXPANDING PULLEY Filed Nov. 16, 1955 2 Sheets-Sheet l B am Fbb.25,1936. M,JANN"4 MULTIPLE GROOVE EXPANDING PULLEY 2 Sheets-Sheet 2 Filed Nov. 1e, 19ss w? ME SH www /V 2R q- A TTORNEYS Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE Application November 16, 1933, Serial No. 698,330 In France December 12, 1932 18 Claims.

The present invention relates to multiple groove expanding pulleys in which the radius of the circumference around which the belt is applied on the pulley can be varied while the pulley is running. Up to the present time, it was known to make expanding pulleys consisting of two flanges with a groove between said flanges so that only one belt could be utilized with such pulleys and the 4 power transmitted was necessarily rather low. The object of the present invention is to provide an expanding pulley having a plurality of grooves each capable of receiving a belt which is both efficient and reliable. Another object of my invention is to provide a change speed gear of the expanding pulley type in which the speed ratio of the driving shaft and of the driven'shaft can be varied gradually.

Still another object of my invention is to provide an expanding pulley change speed gear making use of belts of trapezoidal, section which makes it possible to obtain a considerable range of speeds with relatively narrow belts, the diameter of the circumference along which the belt is applied against the expanding pulleys being constantly kept relatively large.

Preferred embodiments of my invention will be hereinafter described, with reference to the accompanying drawings, given merely by way of example, and in which:

Fig. 1 is a. longitudinal sectional view of a multiple expanding pulley according to my invention;

Fig. 2 is a corresponding end-view;

Fig. 3 is a view similar to Fig. l but corresponding to another embodiment of the pulley according to my invention;

Fig. 4 is a cross sectional view corresponding Fig. 5 is a' longitudinal sectional view of a change speed gear according to myinvention;

Figs. 5a and 5b are detail views of modifications;

Fig. 6 is a detail view on an enlarged scale of another modification;

Fig.. 7 is a diagrammatical sectional view of another embodiment of the change speed device according to my invention.

In the embodiment of my invention shown in Figs. 1 and 2, the pulley is mounted on shaft I provided with a feather key 8. Flanges I, 2, 3, 4, 5, and 6 form the elements of the expanding pulley which, in the example illustrated,. comprises three grooves for the belts. These flanges 55 are suitably bored so as to fit on shaft 1 and they are each provided with a key-way adapted to. The working faces of the flanges are conical over the portion thereof that is to be in contact with the belts. Flanges I, 3, and} are maintained at a fixed distance from one another by means of screws 9 and struts I0. These elements 9- and 10 extend throughout flanges 2,- 4, and 6, which are provided with holes 13 for this purpose. In a likewise manner, flanges-2, 4, and 6, are connected together by means of screws I l andstruts I2 extending through holes 14 provided in flanges I, 3, and 5. The end flanges l and 6 are each provided with a groove l5.

The operation of the pulley that has just been described is as follows: Controlling organs adapted to cooperate with grooves l5 maintain these two flanges l and 6 in the positionshown in Fig. 1. All the flanges are caused to rotate with the shaft through the action of key 8. The belts, only one of which is shown, at 16, in Fig. 1, have their lateral faces applied against the conical faces of the flanges. In order to increase the diameter of the circumference along which the belt is working, it suflices to move flanges I and 6 toward each other by acting on grooves l5. As flange 2 is rigidly connected to flange 6, flanges l and 2 will be moved toward each other, thus compelling the belt to move away from the axis of the shaft, due to the conical shape of the faces of said flanges. The same thing will happen'to the belts located between flanges 3 and 4 on the one hand and between flanges 5 and 6 on the other hand. The position shown in solid lines in Fig. 1 corresponds to the minimum diameter of the circumference around which the belt passes. The position of the flanges for the maximpm'diameter is shown in dotted lines,

one of the three belts being shown at H. With the arrangement shown inFigs. 1 and 2, there must also be provided-means for suitably tensioning thebelts irrespectively of the diameters of the circumferences around which they-pass on the pulleys.

In the embodiment shown in Fig. 3, corresponding elements are designated by the same reference numbers as in the preceding example. Flanges 2,4, and ii are keyed on shaft 1 by means of keys 8. Said flanges are kept at the required distance from one another by struts 26 consisting of sleeves coaxially surrounding the shaft, the whole of these three flanges being applied against a shoulder 21 of the shaft by a nut 28. The other to cooperate with the feather key above referred flanges I, 3, and 5 are slidably connected with sleeves 26 through feather keys 29. These three without requiring any direct action on said flanges.

flanges I, 3, and 5 are maintained at the required distance from one another by threaded rods 30 screwed in these three last mentioned flanges and extending through holes 3I provided in flanges 2, 4, and 6. FlangeI is subjected to the action of a spring 32 which tends to push it toward flange 2.

The operation of this embodiment is as follows: The three belts, only one of which is shown at I6, are pressed laterally between flanges I and 2, 3 and 4, 5 and 6 respectively, owing to the action of spring 32. It results therefrom that the belts adhere to the flanges, thus permitting transmission of efforts. If the tensioning of the belts is reduced, through any suitable means, the flanges move toward one another under the action of spring 32 and the belts are moved away from the axis of the shaft; but they are still compressed between the flanges by the action of spring 32. When the action of the spring and the tension: ing of the belts balance each other, the diameter of the circumferences along which the belts are passing ceases to vary. Accordingly, in this em- .bodment of my invention, the position of the flanges depends on the tensioning of the belts and varies automatically in accordance therewith With the arangement of Fig. 3, feather keys 23 can be dispensed with, the rotary movement of flanges I, 3, and 5 being obtained through screws 30 which are slidably mounted at '35 in flange 6.

I will now proceed to describe the change speed gear of Fig. 5: The driving shaft IOI drives an expanding pulley of a typesimilar to those above described, which is adapted to cooperate with two belts I02 of trapezoidal cross section. This pulley comprises four flanges I03, I04, I05, and

' I06 having conical faces. Flanges I03 and I05 are applied against a shoulder of shaft IOI by a nut I01 and a strut I00. Theyare driven angularly through a key I03. Flanges I04 and. I06, which are free to move axially, are connected together through rods IIO the ends of-which are threaded and provided with nuts, said rods being surrounded by struts III, so as to keep the required distance between .flanges I04 and I06.

There are several groups of rods I I0 and struts III distributed around the shaft, but only one of them has been shown in the drawings. Flanges I05 and I06 are provided with holes through which pass rods III and struts 'III, which also serve to transmit the rotary movement of flanges I03 and I05 to flanges I04 and I06.

Belts I02 pass around another expanding pulley mounted on a parallel lay-shaft II 2. The last mentioned pulley comprises four conical flanges H3, H4, H5, and II6. On the same lay shaft there is provided another expanding pulley comprising four flanges H1, H0, H0, I20. These eight flanges are angularly connected to shaft II2 by key I2I. Flange II4 is kept in a fixed axial position by a thrust bearing I22 mounted in frame I23. Flanges II6, ll1, and IIOare connected to flange II4 throughrods I20 carrying struts I21 interposed between said flanges and the ends of which are threaded so as to receive nuts. ;There are for instance three" groups of said rods and struts distributed angularly about shaft II2 ing-planes making with one another an angle of Manges I", III, IIO, and I20 areconnectedtogetherinthesamewaybymeans of rods I24 and struts I25. The axial position of the four last mentioned flanges is. controlled through a sprocket wheel I20 turninrln a bean therefore eccentrics I64 and thus to modify the .shaft H2 through belts I02.

ing I23 of frame l23 and inwardly threaded. This threaded portion of the sprocket wheel engages with a threaded prolonged part of a cage I30 adapted to slide longitudinally without turning in frame I23 and which forms the outer portion of 5 I two belts I32 of trapezoidal cross section which cooperate with another expanding pulley, co- 1 axially surrounding shaft I M and comprising four flanges I33, I34, I35, and I36. Flanges I34. and I36 are mounted'on a sleeve I31 adapted to turn freely about shaft IM, A key I38 causes sleeve I 31 to be angularly driven by flanges I 34 and I36. Said flanges I 34 and I36 are kept at a given distance from one another by a strut I33, their axial position being fixed. The two sliding flanges I33 and I35 are connected by rods I40 and struts I4I. 'Flange I06 acts on flange I33 through a thrust bearing 142.

Shaft I M carries a spindle I43 at the ends of which are journalled the planet wheels I44 of an epicycloidal gear with bevel wheels. These planet wheels I44 mesh with two sun wheels I45 and 2.3

I41. Sun wheel I45 is driven by sleeve I31 through key I38. Sun wheel I41 is mounted on the driven shaft. A thrust bearing I48 is interposed between shaft IM and sun wheel I 45. This bearingreceives the thrust; of flanges I34 and I36 through the mediumof struts I 39 and I46.

In order to make it possible to vary the tensioning of the belts, I provide a spindle I62 journalled in the lower partof the frame. This spindle is provided at either end with an eccentric disk I64 rigidly fixed thereto, or integral there-' with. Each eccentric disk is journalled in a ring carried by the support I23 of shaft II2. A crank I63 makes it possible to rotate spindle I62 and dista'nce between shaft.

This apparatus works in the following manner: Shaft IOI drives angularly flanges I03, I04, I05, and I06 which transmit this movement to lay Flanges II1,-IIO, II! and I20 in turn .drive belts I32, which drive sleeve 31 and sunwheels I 45. The planet wheel ca y g spindle I43 is rigidly connected to the driving shaft IOI Therefore the speed of rev0lu tion of the driven shaft depends on therelative speeds of shaft IOI and sleeve I31.

If shaft- IOI is supposed'to rotate with a unithe main shaft and the lay form speed of revolution, any variation in' the 5 speed of revolution of sleeve I31 modifies the speed of revolution of the driven shaft. In order'to obtain a variation of the speed of revolution of sleeve 31 while the driving shaft is rotating, it suflices to turn sprocket wheel I26 which causes (2 thrust bearing I3I to move axially in one direction or the other, according to 'the direction of rotation of sprocket wheel I28. If it be supposed, for instance that thrust bearing I3I is pushed toward thrust bearing I22, flanges II1 will move their respective flanges I33 and I34,

I35 and I36 away from one another and this axial 7 ing I42, to flanges I 06 and I04, thus forcing flange I06 against flange I05 and\flange I04 against flange I03, which will absorb the slack of belts I02. After this displacement of the-various parts of the device, the driving pulleys, constituted by flanges I03, I04, I05, I06, and H1, H0, IIQ, I20 will work with an increased diameter of the circumferences of'contact of the belts with the pulleys, while, on the contrary, the driven pulleys, constituted by flanges H3, H4, H5, II6 and I33, I34, I35, I36 will work with a reduced diameter of the circumferences of contact of thebelts with the pulleys. Consequently, the speed of revolution of sleeve I31 will be increased. An angular displacement of sprocket wheel I28 in the opposite direction would of course reduce the speed of revolution of sleeve I31.

When sleeve I31 turns with the same speed of revolution as driving shaft I the driven shaft also rotates with the same speed and in the same direction. In this particular case, the wheels of the epicycloidal gear turn as a whole without any relative displacement of said wheels with respect to one another. This is the direct drive.

If sleeve I31 turns with a speedof revolution smaller than that of the driving shaft, the driven shaft turns in the same direction as the driving shaft but with a higher speed of revolut on.

If the speed of revolution of sleeve I31 is twice that of driving shaft IOI, the driven shaft is stationary. In this case, not only is there no movement transmitted to said driven shaft, but it is prevented from moving. If the speed of revolution of sleeve I31 is then reduced without modifying that of the driving shaft II", the driven shaft is started to revolve in the same direct'on as the driving shaft. On the contrary an increase of 'panding pulleys and an epicycloidal gear.

the speed of sleeve I31 would have started the driven shaft rotating in a direction opposite to that of the driving shaft.

Therefore, the apparatus above described'can be utilized for varying the speed of revolution of the driven shaft with respect to that of the driving shaft, as a brake when the driven shaft is stationary, as a clutch, and as a reversing gear.

In the example shown in Fig. each expanding pulley cooperates with two belts, but it is obvious that each pulley might be devised so as to cooperate with any number of belts, my invention being also applicable to the case of only one belt for each pulley.

The device according to my invention makes it to transmit a high power with a range of speed variation as wide as it is desired. This result is obtained by making use of two groups of ex- Al'- though this result might be obtained with a single group of expanding pulleys, the device above described has the advantage of reducing to the square root of the total ratio of speed variation, the maximum variation for each group of expanding pulleys. Thus it has been above explained that the variation of the speed of revolution of the driven shaft from zero to that corresponding to direct drive is obtained by varying the ratio of the angular velocities of driving shaft IOI and of sleeve I31 between 1 and 2, this variation being obtained through the combined action of the four expanding pulleys. As it is advantageous, for practical purposes, to obtain with the same apparatus both reverse gear and an angular velocity of the driven shaft higher than that of the driving shaft, the above ratio should be able to be varied, say, between 0.8 and 2.2. It

will therefore suffice that each group oftwo cooperating pulleys should have a speed ratio ranging between 0.9 and 1.48. Thisharrow range of variation is very favorable to a good transmission of the movement since it makes it possible to utilize belts of relatively narrow width as compared to their thickness, moving on the 'pul leys along circumferences of relatively large die ameter. It is a known fact that relatively wide belts are apt to buckle and that the fact of moving along circumferences of small diameter is a cause of rapid wear of the belts. Besides, the same results could be obtained with a still narrower range of speed ratio variation. It would sufllce to utilize a differential gear of suitable gear ratio, for instance one with cylindrical wheels as shown in Fig. 5b, in which the numof the angular velocities of the driving shaft and of the driven shaft is obtained by moving flanges H3, H5, H6, and I along lay shaft II2 so as to reduce the working diameter of one of the pulleys mounted on said shaft and to increase the working diameter of the other pulley provided on said lay shaft. Furthermore, through the medium of the belts and of thrust bearing I42, a displacement of flanges H3, H5; H8, and I20 produces a displacement in the same direction of flanges I04, I06, I33, and I so that each of the belts is always maintained in a; planeat right angles to the axes of the pulleys.

The tensioning of belts I02 produces a thrust on flanges I03 and I05 which tends to move shaft. I0'I toward the right hand side. In a likewise manner belts I32 tend to push flanges I34 These two' .The working faces of the flanges that go to make the pulleys are of conical shape, however in order to obtain a constant tensioningof the belts whatever be the ratio of transmission that is chosen, it may be advantageous to modify that shape either by curving them or by giving to the angle of the cone a value slightly different for some flanges.

Such an arrangement is shown in Fig. 6 in which the peripheral portions of the flanges are curved. This shape has the advantage of ensuring a constant tensioning of the belts irrespectively of the diameter of the circumferences along which they contact the flanges. Furthermore, as

the trapezoidal cross section of each belt is deformed when the diameter of the circumference along which it is wound on the flange is changed,

' shaft u: might be of the type shown in Figs.

3 and 4. They may be of the type shown in Fig. 6, in which flanges IIl, III, III, and III are connected together by a rod screwing in said flanges andextending freely through holes pro- .vided in the other flanges Ill, III, III, Ill, while flanges Ill, II6,.III, II! are connected together by rods screwing in the last mentioned flanges and extending freely through holes provided in the other flanges H3, Iii, H8, and I.

The control of the speed ratio variation may be performed either automatically or manually. Fig. 7 is a diagrammatical view of another embodiment of the change speed gear according to my invention. In this flgure I have shown in solid lines the flanges that are flxed in the axial direction and in dotted lines the flanges that may slide in said axial direction. The driving shaft I'M drives a pulley I5I which is hollow and carries planet wheels I journalled therein and meshing with sun wheels I45 and I" of the epicycloidal gear. The lay shaft III is flxed in frame I23 through eccentric bearings I 51. The pulleys mounted on the lay shaft consist of two drums I58 and I59 sliding with respect to each other and adapted to rotate together. Drum I58 cannot move in the axial direction and determines the axial position of theflanges shown in solid lines. The flanges shown in dotted lines are connected to drum I59 the axial position of which is controlled through a sleeve IGI slidably keyed on the lay shaft. This sleeve I6I is moved in the axial direction by sprocket wheel I28 in which it is screwed, in the same manner as above described with respect 'to Fig.5.

The working of the embodiment Just above described is the same as that explained with respect to the embodimentof Fig. 5. However, in this case the pulleys mounted on the lay shaft turn with respect to said shaft which is stationary and which can, through eccentrics I51, vary the tensioning of the belts; even when the device is running. Furthermore, as the epicycloidal gear and the means for controlling the axial displacements of the movable flanges are located inside the pulleys, the room occupied by the device is considerably reduced.

Apparatus of the type above described canbe applied to mechanisms in which it is necessary, or desirable, to have a variable speed ratio trans mission, such as machine tools, conveying apparatus, automobile vehicles, etc. The apparatus according tomy inven. ion are also applicable to the cases in which a stationary shaft must .be first maintained in a flxed position and then progressively actuated in one direction or the other, with a load applied thereon as soon as it starts moving, as it is the case in particular for automotive vehicles, for, tractors or for hoistingengines. The apparatus according to my invention are also adapted to the control of a shaft or other organ the motion of whichis proportional to that of the operating apparatus such as a rudder or the turret of a warship.

While I have described what I deem to be prac-v tical andefllcient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changesa through said flanges,

for detachably forcing r 9,081,712 I f th without departing from the principle of my invention as comprehended within the scope of the appended claims. ,7

What I claim is:

1; An expanding pulley adapted to be mounted on a shaft, which comprises in combination, a series of flanges mounted in juxtaposition on said shaft so as to form a plurality of pairs each adapted to accommodate a belt between its flanges the respective faces of the two flanges of a pair that are in contact with the belt being inclined so as to cause the belt to move radially with respect to the shaft when two flanges are given a relative axial displacement, a plurality of rods extending throughout said flanges, means on said rods for removably flxing in a rigid manner the even numbered flanges of said series relatively to'one another in the axial direction while allowing said even numbered flanges to movewith respect to the odd numbered flanges, means wholly independent, for relative displacements in the axial direction, of the last mentioned means for removably connecting together in a rigid manner all the odd numbered flanges of said series, means for angularly connecting said flanges to said shaft, and means for producing relative axial displacemens of the whole of the even numbered flanges and of the whole of the odd numbered flanges.

2. An expanding pulley adapted to be mounted on a shaft, which comprises in combination, a series of flanges mounted in juxtaposition on said shaft so as to form a plurality of pairs each adapted to accommodaie a belt between its flanges, the respective faces of the two flanges of a pair that are to be in contact with the belt being inclined so as to cause the belt to move radially with respect to the shaft when said two flanges are given a relative axial displacement, a plurality of rods parallel to said shaft extending a plurality of tubular struts surrounding said rods and each interposed between two consecutive even numbered flanges and adapted to slide freely, in the axial direction, with respect to the odd numbered flanges, means the second flange of the series toward the last flange of said series, a plurality of rods parallel to said shaft extending' through said flanges, a plurality of tubular struts surrounding the last mentioned rods and interposed between two consecutive odd numbered flanges of the series, means for the first flange of the series toward the last odd numbered flange of the series, and means for slidably keying said flanges onsaid shaft.

3. An expanding pulley adapted to be mounted on a shaft, which comprises in combination, a series of flanges mounted in iuxtaposition onsaid shaft so as to form a plurality of pairs each adapted to accommodate a belt between its flanges, the respective faces of the two flanges of 'a pair that are to be in contact with the belt detachably fore-- being inclined so as to'cause the belt to move radially with respect to the shaft when said two flanges are given a relative plurality of rods screwed in allof' e odd numbered flanges of the; series, theeven. numbered flanges being provided with holes through which said rods can slide freely, means for rigidly con-' necting together all the even numbered flanges of the series, means for angularly'connecting said flanges to said shaft, and elastic means for urging the oddnumbered flanges against the even numbered flanges respectively.

4. An expanding pulley, according to claim 3.

axial lacement, a

in which the means for rigidly connecting together all the even numbered flanges comprise a series of tubular struts coaxially mounted on.

said shaft each between two consecutive even numbered flanges, the odd numbered flanges being coaxially mounted on said tubular struts, the means for angularly connecting said flanges to said shaft comprising keying means interposed between said-shaft, on the one hand, and said tubular struts and even numbered flanges, on the other hand.

5. An expanding pulley according to claim 3 in which the means for rigidly connecting together all the even numbered flanges comprise a series of tubular struts coaxially mounted on said shaft each between two consecutive odd numbered flanges, the odd numbered flanges being coaxially mounted on said tubular struts, the means for angularlyconnecting said flanges to said shaft comprising keying means interposed between, said shaft, on the one hand, and said tubular struts and even numbered flanges, on the other hand, and keying means interposed between said tubular struts and said odd numbered flanges.

6. An expanding pulley according to claim 3 in which the even numbered flanges are fixed in the axial direction with respect to said shaft and the elastic means are interposed between said shaft and said odd numbered flanges.

'7. An expanding pulley according to claim 1 in which the means for rigidly fixing the even numbered flanges relatively to one another in the axial direction consist of screen threads provided on said rods and screwed in said even numbered flanges, the odd numbered flanges being provided with holes through which said rods can slide freely, and the means for rigidly connecting together the odd numbered flanges consist of a plurality of rods screwed in all of said odd numbered flanges, the even numbered flanges being provided with holes through which the last men tioned rods can slide freely.

8. In combination with an expanding pulley including a shaft and two flanges angularly flxed on said shaft and adapted to move relatively to each other in the axial direction of said shaft. the respective inner faces of these two flanges being inclined toward the intermediate part of the shaft so as to cause a belt inserted between said flanges to move radially with respect to said shaft when said two flanges are given a relative axial displacement, a device for controlling these relative axial displacements which comprises in combination, a support flxed in the axial direction with respect to one of said flanges, two members screwing in each other about the axis of said shaft, one of said members being journalled. in said support coaxially with said shaft, the other being slidably keyed in said support parallelly to said shaft, means for controlling the angular displacements of the first mentioned member and means for axially connecting the second mentioned member and the other flange.

9. In combination with an expanding pulley including a shaft and two flanges angularly flxed on said shaft and adapted to move relatively to each other in the axial direction of'said shaft, the respective inner faces of these two flanges being inclined toward the intermediate part of the shaft so as to cause a belt inserted between said flanges to move radially with respect to said relative axial displacements of the two flanges,

which comprises in combination, a frame, means for flxing one of said flanges with respect to said frame in the axial direction thereof, a sprocket wheel provided-with internal threads journalled in said frame coaxially with said shaft, a tubular member screwing in said sprocket wheel coaxially with said shaft and adapted to slide in said frame parallelly to said shaft but prevented from rotating therein, a sleeve rigidly connected to the other flange, and a thrust bearing interposed between said tubular member and said sleeve.

. 10. In a variable speed power transmission device, the combination of three parallel shafts,

operatively connecting with each other the two secondmentioned pulleys so that an increase in the working diameter of one of these two second mentioned pulleys causes a reduction of the working diameter of the other of said two second mentioned pulleys, and means for controlling the working diameter of one of said second mentioned pull ys- 11. In a variable speed power transmission device, the combination of three parallel shafts, two expansible pulleys keyed on the first and second shafts respectively, two expansible pulleys both keyed on the third shaft opposite said two first mentioned pulleys respectively, at least one axially movable flange in each of these pulleys, belts connecting together the pulleys mounted opposite each other respectively, means for operatively connecting together the axially movable flanges of the two flrst mentioned pulleys so that a sliding displacement of one of these last mentioned flanges in the direction that increases the working diameter of its respective pulley causes a sliding displacement of the axially movable flange of the other of these flrst mentioned pulleys in the direction that decreases the working diameter of said last mentioned pulley, means for operatively connecting together the axially movable flanges of the two second mentioned pulleys so that a sliding displacement of one of these last mentioned flanges in the direction that increases the workingdiameterof its respective pulleycauses a sliding displacement of the axially movable flange of the other of these two second mentioned pulleys in the direction that decreases the working diameter of said last mentioned pulley,

' and means for controlling .the axial position of shaft opposite said two first mentioned pulleys respectively, at least one axially movable flange in each of these pulleys, belts connecting together the pulleys mounted opposite each other respectively, means for operatively connecting together the axially movable flanges of the two first men-. tioned pulleys so that a sliding displacement of these two first mentioned pulleys in the direction that decreases the working diameter of said last mentioned pulley, means for operatively connecting together-the axially movable flanges of the;

two second mentioned pulleys so that a sliding displacement of one of these last mentioned flanges in the direction that increases the working diameter of its respective pulley causes a sliding displacement of the axially movable flange of the other of these two second mentioned pulleys in the direction that decreases the working diameter of said last mentioned pulley, and means for-controlling the axial position of at least one of the last mentioned axially movable flanges with respect to the third shaft. I

13. A combination according to claim 12 in which the second shaft consists of a sleeve surrounding the first shaft.

14. In a variable speed power transmission device, the combination of two shafts in line with each other, a third shaft parallel to these two first mentioned shafts, two expansible pulleys keyed on the first and second. shafts respectively, two expansible pulleys keyed on the third shaft opposite said two first mentioned pulleys respectively, each of these pulleys including a series of flanges mounted in juxtaposition on the corre sponding shaft so as to form a plurality of-pairs I each adapted to accommodate a belt between its flanges, the respective faces of the two flanges of a pair that are in contact with the belt being inclined so as to cause the belt to move radially with respect to the shaft when two flanges are given alrelative axial displacement, a plurality of rods extending throughout said flanges, means on said rods for rigidly fixing the even numbered flanges of said series relatively to one another in the axial direction, and means for rigidly connectingtogether all the odd numbered flanges, of said series, belts connecting together the pairs of flanges mounted opposite each other on the third shaft and the first and second shafts respectively, means for axially connecting an even numbered flange of one of the two first mentioned pulleys with an odd numbered flange of the other of said two first mentioned pulleys, so that an increase in the working diameter of one of the two first mentioned pulleys causes a reduction of the working diameter of the other of said two first mentioned pulleys, means for rigidly connecting together the even numbered flanges of one of the twosecond mentioned pulleys with the odd numbered flanges of the other of said second mentioned pulleys, so that an increase in the working diameter of one of the two second meritioned pulleys causes a reduction of the working diameter of the other of these two second mentioned pulleys, and means for controlling the axial positions of the axially movable flanges of the two second mentioned pulleys with respect to said third shaft.

15. In a variable speed power transmission device, the combination of two shafts in line with each other, a third shaft parallel to these two first mentioned shafts, 'two expansible pulleys keyed on the first and second shafts respectively, two expansible pulleys keyed both on the third shaft opposite said two first mentioned pulleys respectively, each of these pulleys including a series of flanges mounted in juxtaposition on the correspondingshaft so as to form a plurality of pairs each adapted to accommodate a belt between its flanges, the respective faces of the two flanges of a pair that are in contact with the belt being inclined so as to cause the belt to move radially with respect to the shaft when two flanges are given a relative axial displacement, a plurality of rods extending throughout said flanges, means on said rods for-rigidly fixing the even numbered flanges .of-said series relatively to one another in the axial direction, and means for 10 rigidly connecting together all the odd-numbered flanges of said series, belts adapted to connect together the pairs of flanges mounted opposite one another on the third shaft and the first and second mentioned shafts respectively, 15 a thrust ball bearing interposed between an even-numbered flange of one of the two first mentioned pulleys and an odd-numbered flange of the other of said two first mentioned pulleys, whereby an increase in the working diameter of one of said two first mentioned pulleys causes a reduction of the working diameter of the other of said two first mentioned pulleys, means for rigidly connecting together the even-numbered flanges of one of the two second mentioned pulleys with the odd-numbered flanges of the other of said second mentioned pulleys, so that an increase in the working diameter of one of the two second mentioned pulleys causes a reduction ofthe working diameter of the other of these 30 two second mentioned pulleys, and means for controlling the axial positions of the axially movable flanges of the two second mentioned pulleys with respect to said third shaft.

16. A power transmitting device. which compises in combination, a shaft, at least two flanges, means for moving said flanges relatively to each other in the direction of the axis of said shaft, the peripheral portions of the faces of said flanges that are turned toward each other being each in the shape of a surface of revolution approximating a portion of a cone, but with a slight curvature the convexity of which is turned toward the other flange of the pair, and a belt of trapezoidal section made of a deformable material having its inclined faces applied against said faces of the flanges.

17. An expanding pulley adapted to be mounted on a shaft, which comprises, in combination,

a series of flanges mounted in juxtaposition on said shaft so as to form a plurality of pairs each adapted to accommodate a belt between its flanges, the respective faces of the two flanges of a pair that are in contactwith the beltbeing 55 inclined so as to cause the belt to move radially with respect to the shaft when said two flanges are given a relative axial displacement, a plurality of rods parallel to said shaft extending through said flanges, a plurality of tubular struts surrounding said rods and each interposed between two consecutive even numbered flanges, each of said rods being threaded at one end and provided with a head at the other end so as to force the second flange of the series toward the last flange of said series, a plurality of rods parallel to said shaft extending through said flanges, a plurality of tubular struts surrounding the last mentioned rods and' each interposed between two consecutive odd numbered flanges of the series, each of said last mentioned rods being threaded at one end and provided with a head at the other end so as to force the first flange of the series v toward the last odd numbered flange oi! said se- 7 ries, and means for slidably keying said flanges on said shaft.

18. In a variable speed power transmission device, the combination of three parallel shafts, two expansible pulleys keyed on the first and second shafts respectively, two expansible pulleys both keyed on the third shaft opposite said two first mentioned'pulleys respectively, at least two fianges'in each pulley axially slidable with respect to each other, belts connecting together the pulleys located opposite each other respectively,

means for operatively connecting together the axially movable flanges of the two first mentioned pulleys so that a sliding displacement of one of these lastmentioned flanges in the direction that increases the working diameter of its respective pulley causes a sliding displacement of the axially movable flange of the other of these two first'mentioned pulleys in the direction that decreases the working diameter of said last mentioned pulley, means for axially connecting together the first flangeof one of the two second mentioned pulleys to the second flange of the other of said second mentioned pulleys, means for axially connecting together the second flange of the first of said second mentioned pulleys to the first flange of the second of these two second mentioned pulleys, a frame in which said shafts are journalled, means for fixing one of the flanges of the two second mentioned pulleys on the third shaft in the axial direction thereof,-a sprocket wheel provided with threads journalled in said frame coaxially with said third shaft, a tubular member screwing in said sprocket wheel coaxially with said third shaft and adapted to slide in said frame parallelly to said shaft, but prevented from rotating therein, a sleeve rigidly connected to one ofthe flanges of said two second mentioned pulleys that are slidable with respect to said third shaft, and a thrust bearing interposed between said tubular member and said sleeve..

- MARCEL'JANNIN. 

